/*
 * Alloy Analyzer 4 -- Copyright (c) 2006-2008, Felix Chang
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package edu.ut.ece382c.valloy.ast;

import edu.mit.csail.sdg.alloy4.Pos;
import edu.mit.csail.sdg.alloy4.Err;
import edu.mit.csail.sdg.alloy4.ErrorType;
import edu.mit.csail.sdg.alloy4.JoinableList;

import static edu.ut.ece382c.valloy.ast.Type.EMPTY;

/**
 * Immutable; represents an illegal relation join.
 *
 * <p> <b>Invariant:</b>  this.type==EMPTY && this.errors.size()>0
 */

public final class ExprBadJoin extends Expr {

    /** The left-hand-side expression. */
    public final Expr left;

    /** The right-hand-side expression. */
    public final Expr right;

    /** Caches the span() result. */
    private Pos span=null;

    /** {@inheritDoc} */
    @Override public Pos span() {
        Pos p=span;
        if (p==null) span = (p = pos.merge(closingBracket).merge(right.span()).merge(left.span()));
        return p;
    }

    /** {@inheritDoc} */
    @Override public void toString(StringBuilder out, int indent, boolean newline) {
    	for(int i=0; i<indent && newline; i++) { out.append(' '); }
    	
    	//
    	// XXX hack to deal with the syntax A[B,C, ...] which can mean a join operation
    	// or a function/predicate call
    	//
    	if ((left instanceof ExprList) && (((ExprList)left).op == ExprList.Op.JOIN )){
    		//
    		// 'special' join case
    		//
    		right.toString(out, indent, false);
    		left.toString(out, indent, false);
    	} else {
    		//
    		// 'normal' join case
    		//
    		left.toString(out, indent, false);
    		out.append('.');
    		right.toString(out, indent, false);
    	}
    }

    /** Constructs an ExprBadJoin node. */
    private ExprBadJoin(Pos pos, Pos closingBracket, Expr left, Expr right, JoinableList<Err> errors) {
        super(pos, closingBracket, (left.ambiguous || right.ambiguous), EMPTY, 0, 0, errors);
        this.left=left;
        this.right=right;
    }

    /** Constructs an ExprBadJoin node. */
    public static Expr make(Pos pos, Pos closingBracket, Expr left, Expr right) {
        JoinableList<Err> errors = left.errors.join(right.errors);
        if (errors.isEmpty()) {
            StringBuilder sb=new StringBuilder("This cannot be a legal relational join where\nleft hand side is ");
            left.toString(sb,0, false);
            sb.append(" (type = ").append(left.type).append(")\nright hand side is ");
            right.toString(sb,0,false);
            sb.append(" (type = ").append(right.type).append(")\n");
            errors = errors.append(new ErrorType(pos, sb.toString()));
        }
        return new ExprBadJoin(pos, closingBracket, left, right, errors);
    }

    /** {@inheritDoc} */
    public int getDepth() {
        int a=left.getDepth(), b=right.getDepth();
        if (a>=b) return 1+a; else return 1+b;
    }

    /** {@inheritDoc} */
    @Override final<T> T accept(VisitReturn<T> visitor) throws Err { return visitor.visit(this); }
}
